Febr3 Lewis Structure, Characteristics: 5 Facts You Should Know

Iron (III) Bromide (FeBr3) has quite stable polymeric structure, generally known as Ferric bromide.

The brown color solid inorganic compound can be used as oxidant, removes electron in redox reaction or used as catalyst in bromination where concentration of FeBr3 remains same after and before reaction but it affect the rate of reaction.

How to draw febr3 lewis structure?

With using the atomic symbols, the FeBr3 lewis structure shows the distribution of the outer orbit electrons in formation of the molecule, as an ionic compound for the electronic transition the charges are shown upper outside of bracket around atom.

Count the valence electrons of the molecule:

In modern Periodic table the halogen atom Bromine is in group 17 with outer shell electronic distribution in 4s, 4p orbital: [Ar] 3d10 4s2 4p5 where Iron is in group no 8 and being transition metal with incomplete electronic arrangement in 3d orbital; [Ar] 3d6 4s2.

Outer orbit electrons are mostly loosely bounded by nucleus force but in addition the d orbital being more diffused in nature it can easily exchange electron cloud. Orbital is energetically most stabilized in their full filled or half filled electronic configuration.

Cover the Octet rule:

To form energetically stable molecule (unreactive), all atoms must have full filled last orbit with eight electrons by transferring electrons, referred as Octet rule.

Iron transfers three electrons from 4s and 3d jointly results remaining of five electrons in 3d orbital, which is a stabilize configuration for the half filled 3d orbital and forms Iron (III). The electrons are accepted by the vacant 4p orbital to satisfy the stabilization rule.


febr3 lewis structure
FeBr3 lewis structure electronic arrangement

Calculate the formal charge of the individual atom:

As FeBr3 is ionic molecule so the formal charge is not calculated where we consider the electro-negativity of individual atoms, opposite of the covalent molecule, where the electron pulling ability of atoms is consider equally.

Skeletal formation of the BrCl lewis structure:

FeBr3 is a tetra-atomic molecule, where Iron (Fe) is the central atom, more electro positive than halogen atom. The atomic symbols are written inside brackets, by electron transferring they possess charges which are shown outside of bracket.

Is febr3 ionic or covalent?

When metal and non-metal elements from molecule, there fully electronic transfer is occurred from metallic orbital to vacant non-metallic orbital in spite of electron cloud sharing, produces ionic compound.

Bromine is a non metal element where Iron is a transition metal element, are joined together by fully transferring electron cloud of Fe having diffused 3d orbital electron to vacant 4p orbital of halogen atom, hence FeBr3 lewis structure is ionic in nature.  

Being an ionic molecule we can see the melting point of the FeBr3 lewis structure is quite high, (200 ̊ C) as the opposite charges are bound by strong electrostatic force and are arranged in a proper design of repetition in crystalline structure, result in a high lattice energy.

Is febr3 an acid or base?

FeBr3 lewis structure contains Fe atom which is a transition metal having 3d orbital, and Fe combines with electro-negative halogen atom Br, makes the molecule a lewis acid, capable of accepting electron.

In metal halide FeBr3, because of difference in electron cloud pulling capability Fe contains partial positive charge and because of having vacant 3d orbital it adopted electron pair accepting ability, as a result used as a catalyst in aromatic bromination reaction.

In bromination of Benzene FeBr3 is used with Br2 for its strong lewis acid nature, it polarizes the Bromine molecule with partial charges and combine with it by accepting electron cloud which makes easy for benzene electron cloud to do nucleophilic attack.

febr3 lewis structure
electron transfer into FeBr3 lewis structure

Is febr3 soluble?

FeBr3 solubility in any solvent is measured by the amount of concentration that can be dissolved until the equilibrium occurs means the concentration of reactant compound and the product compound result balance in that condition (like temp.)

Solubility in water:

As a polar solvent, water (H2O) has partial charges over it for difference of electro-negativity between atoms and can dissolve polar molecules. Because of greater power of pulling electron cloud toward it, Oxygen carries partial negative charge.

FeBr3 has Iron atom which has (+3) charge over it as it transfer two 4s and one 3d electrons and three Bromine atoms which accepts electrons so that have negative charge (-1), so charge separation is there and as a result can easily dissolve in water like polar solvent.

Solubility in ether:

Ether has polar Carbon- Oxygen bond (Oxygen is highly electronegative than Carbon) as its molecular formula is R-O-R´ where R and R´ are two different alkyl groups, so it has some dipole moment  causes ether a polar solvent.

FeBr3 is an ionic compound, contains oppositely charged ions bounded with electrostatic force, so can dissolve in polar solvent. But the polarity differs with length of hydrocarbon chain of ether as with increasing it the interaction between ether and FeBr3 decrease.

Solubility in ethanol:

Methanol, ethanol or propanol have small hydrocarbon chain (hydrophobic part) with the hydroxyl group (-OH) which is polar for Oxygen atom with high electro-negativity (electron pulling ability) result in becoming polar solvent.

So ionic compound like FeBr3, having charge distribution can soluble in ethanol.

Is febr3 a salt?

A salt have two portion called cation with positive charge and anion with negative charge, the amount of the charge will be equal so that the salt molecule will be neutral without any charge. If they contain the ionic part forming with one atom, are called monatonic salt.

In neutralization reaction, FeBr3 is formed having oppositely charged metal ion iron (III) and non-metal bromide ion, and as one iron atom combines with three bromide ions, produces neutral salt. As the ionic parts are not combination of atoms, the salt is monatomic.

In the neutralization reaction of strong acid (HBr) and weak base (Fe(OH)3) where the strong acid is neutralized and forms the ionic compound as salt FeBr3 and water.

Being an ionic compound Salts have some crystalline structure where the ions are arranged in certain manner of repetition which also can be seen in case of FeBr3 lewis structure where it crystallizes in the trigonal R-3 space group.


Having transition metal, iron with ‘d’ orbital effects properties of FeBr3.

Triyasha Mondal

Hi...I am Triyasha Mondal, pursuing M.Sc in Chemistry. I am an enthusiastic learner. My specialization is in physical chemistry. Let's connect through LinkedIn:https://www.linkedin.com/in/triyasha-mondal-a4b553249

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